Adrian Alexander Mann created a piano with bass strings that are unwound and are at full linear length relative to the pitch they produce.

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Conceptual sculptor Bjorn Perborg built a 5 key piano as part of a gallery show, according to him the inspiration for the piano is “I showed an installation about the Collyer brothers, two hoarders who lived like hermits in Manhattan during the first half of the 20th century. One of the brothers used to be a concert pianist and I thought a crippled piano could go well with their story.”

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A Loja de Pianos constructed a copy of the 5 key piano, which is now owned and used by Fabricio André Bernard Di Paolo known on Youtube as Lord Vinheteiro

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Wayne Stuart and his company Stuart and Sons has released a piano called the Beleura which has a range of 108 notes.

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William A. Sethares constructed a prototype of the Hyperpiano, a piano with the string modified to no longer be of consistent thickness, which each string having segments of thicker and thinner wire, which makes the instrument have a vastly different set of harmonics then a standard piano.

Percy Grainger created a 1/6th tone piano to use in his musical compositions.

Doug Blackley- Inventor of the Spectrumpiano.
Percy Grainger- Built a 1/6th tone piano known as the Butterfly Piano
David Klavins- Maker of experimental and expanded function pianos known for the M450 and the Una Corda
Sarah Nicolls- Builder of the Future Piano and the Inside Out Piano, she is interested in expanding the piano.
William A. Sethares- Inventor of the Hyperpiano.
Wayne Stuart- Maker of the Beleura a 108 key piano
Adrian Alexander Mann- Builder of the Alexander Piano, a piano with extended bass strings.
Bjorn Perborg- builder of a functioning sound sculpture that is a 5 key piano